<template>
  <div>
      Father
      <input v-model="title" type="text">
  </div>
  <Son @sendNum="fn" :msg="title" />
</template>

<script>
import { ref } from '@vue/reactivity'
import Son from './Son.vue'
export default {
    setup() {
        const title = ref('标题')
        const fn = (data) => {
            console.log(data.value)
        }
        return {
            title,
            fn
        }
    },
    components: {
        Son
    }
}
</script>

<style>

</style>